1. Field of the Invention
The subject matter of the present invention is directed to a washing machine and more particularly to a machine that is to automatically dispense the necessary cleaning and treatment chemicals at the proper times in optimally measured doses within the wash basin of the machine.
2. Description of the Related Art
Automatic washing machines for cleaning of dishes and clothes have long been known. Most automatic washing machines are designed to dispense the proper amount of water within the wash basin of the machine or to control the size of the load that is to be handled by the machine. In a clothes washing machine, different chemicals are commonly provided. These different chemicals include detergent, bleach and softeners. It would be desirable to insure that the precise amount of each chemical is to be dispensed according to what parameters have been programmed into the machine. The programming of the parameters are to be accomplished by the user. In other words, the user would program in whether the clothes were white clothes or colored clothes and whether it is a light load, a medium load or a heavy load. Once these parameters have been inserted into the machine, it would be desirable to have the machine dispense the exact amount of chemicals at the correct times within the wash basin of the machine. In the past, there has not been known a machine that has been designed to achieve this end result.
There are numerous prior art automatic washing machines which are designed to sense the type and/or volume of material to be washed or the soil level of the articles that are to be washed. This knowledge is to allow the machine to adjust the amount of water, the rinse type and the motor action to enhance the cleaning and minimize garment degradation. However, these prior art machines still require the user to manually dispense cleaning and treatment agents into the machine. There is a potential for dosing mistakes in relation to the manual selection of the amount of the cleaning agent and at the time that it is to be inserted in conjunction with the machine. These dosing mistakes lead to inefficient cleaning and even possible damage when the article being cleaned is clothing.
Reference is to be had within the prior art to U.S. Pat. Nos. 3,881,328 and 3,982,666 that describe a dispensing system which is triggered by a signaling device in the washing machine to activate and deactivate solenoid valves allowing injection of various liquid cleaning products through venturi-aspirators into a water feed hose of a machine with a timing circuit to control the amount dispensed. A similar system is described in U.S. Pat. No. 4,103,520 where a plurality of liquid additives can be injected in a predetermined sequence under the control of an adapter which is interfaced with the washing machine. The adapter includes a programmable timer to control the injection volume and sequence. Another machine, outlined in U.S. Pat. No. 4,932,227, senses flow into the washing machine water feed lines as a stimulus for a control head to selectively activate a plurality of chemical injection pumps. U.S. Pat. No. 5,207,080 lists an apparatus that monitors the electrical current draw of the washing machine to determine when the detergent should be injected into the washing machine. U.S. Patent application 2003/0116177 describes a non-intrusive automatic dosing system which senses at least one parameter from the washing machine to activate pumped chemical injection into the water feed line of the washer. One significant problem dealing with this approach is the requirement for multiple pumps which are expensive and require the use of expensive electrical power. The main disadvantage of all the aforementioned prior art machines is that such are not integrated into the washing machine and therefore not privy to the knowledge gained from user input. These prior art machines do not have a method for determining the current washing machine cycle steps. Assumptions must be made as to sequence and duration of the cycle steps which varies among machines and wash types. Further complicating the issue is the fact that in order to make some prior systems responsive the user would be required to input data twice, once to the machine and once to an adapter. The machine is still without a guarantee of proper function due to the lack of a robust feedback mechanism. Another drawback is the method of measurement of chemicals. These systems rely on timing circuits to determine the chemical dose which is indirect and subject to error. The fluid properties (density and viscosity), which affect the flow rate and thus volume measured, are not constant among all products (detergents have different properties and so do fabric softeners, etc.). Also, density and viscosity vary among the different brands of the same product. Without this knowledge, the measurement can lead to error and thus inefficient or possibly harmful chemical dosing.
U.S. Pat. No. 4,503,575 takes some of the prior issues into account. This fully integrated washing machine collects user input and sensor acquired knowledge to make decisions about the type of chemicals needed. It then circulates water, determines the weight of the clothes and fills the reservoir. A metered amount of water is then removed from the reservoir and replaced with the same volume of chemical as measured by pressure. This metering and replacing can occur as many times as necessary before the reservoir contents are pumped into the wash basin. Though this design eliminates some drawbacks of the prior art devices, it still has some problems. First the design is not efficient in its use of energy, requiring continual recirculation to insure that the chemical contents in the reservoir are completely dispensed into the wash basin. Modern, high efficiency washers save energy by not continually pumping water during the beginning cycle, making this approach impractical. Manual loading of the chemical supply reservoirs by the user still allows for potentially serious problems. For example, bleach could accidentally be spilled into a detergent or softener receptacle ruining certain clothes, a liability which cannot be tolerated.